Converting to Catholicism is normally done via the RCIA ~ the Rite of Christian Initiation of Adults. There is a preparation course, which has a small nominal cost of course materials.
Anglican Catholic Answer!
Everyone who is validly baptised, by water and by word becomes a Catholic! Normally one would be taught the Faith once revealed by Christ to the saints and this would be confirmed by the Bishop through a ceremony of anointing or Chrismation! If one wishes intently to believe and does follow the teaching as he or she understands it, then he will be within the Church , all one has to do is pay a call to your parish priest . Beyond time and effort there is usually no cost!